\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{circuitikz}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\ctikzset{bipoles/length=1cm}
\begin{document}
\small
\begin{circuitikz}[>=latex, scale=1.0,european]
  % \useasboundingbox(0.9,0)rectangle(5.1,5);
  \draw(3,0)to [battery2,name=dc] (0,0)--(0,1.2) to [rmeter, t=V, *-*] (6,1.2)--(6,0);
  \draw (3,0) to [cute open switch=$K$] (6,0);
  \draw(0,1.2)--(0,2.2)--(1,2.2) to [pR,name=hb] (2,2.2) to [rmeter, t=A] (6,2.2)--(6,1.2);
  \draw(.35,2.2)--(.35,2.2|-hb.wiper)--(hb.wiper);
  \node at (hb.center)[below=1.5mm]{$R$};
  \node at (dc.center)[above=2.5mm]{$\mathcal{E}, \; r$};
\end{circuitikz}
\end{document}